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| Share Name | Share Symbol | Market | Type | Share ISIN | Share Description |
|---|---|---|---|---|---|
| Thor Energy Plc | LSE:THR | London | Ordinary Share | GB00BRJ52319 | ORD GBP0.001 |
| Price Change | % Change | Share Price | Bid Price | Offer Price | High Price | Low Price | Open Price | Shares Traded | Last Trade | |
|---|---|---|---|---|---|---|---|---|---|---|
| 0.00 | 0.00% | 1.20 | 1.10 | 1.30 | 1.20 | 1.20 | 1.20 | 64,216 | 08:00:00 |
| Industry Sector | Turnover | Profit | EPS - Basic | PE Ratio | Market Cap |
|---|---|---|---|---|---|
| Misc Nonmtl Minrls, Ex Fuels | 0 | -520k | -0.0019 | -6.32 | 3.34M |
From Apr 2019 to Apr 2024
TIDMTHR
RNS Number : 3654P
Thor Mining PLC
10 October 2019
10 October 2019
MOLYHIL MINERAL RESOURCE ESTIMATE ENHANCED
The Board of Thor Mining Plc ("Thor") (AIM, ASX: THR) is pleased to advise of an update to the Mineral Resource Estimate for the Company's flagship Molyhil project in the Northern Territory of Australia.
Highlights
-- The Molyhil Mineral Resource now comprises Indicated and Inferred Mineral Resources of 4.7 million tonnes at 0.28% WO (Tungsten trioxide), 0.14% Mo (Molybdenum), 0.05% Cu (Copper), and 18.0% Fe (Iron) (above a cut-off grade of 0.12% WO(3) equivalent) (Refer to Table A below);
-- The revised resource estimate increases contained WO by 1.5% , and contained Mo by 9.3% compared with the previous estimate;
-- The Mineral Resource, is further boosted with the inclusion of copper in the resource inventory, contributing an additional potential by-product stream for the project;
-- Metallurgical process test work has demonstrated the capacity to produce a separate copper concentrate from Molyhil ore with minimal additional cost.
Mr Mick Billing, Executive Chairman, commented:
"This revised Mineral Resource Estimate is a welcome boost for the Molyhil project with a 1.5% increment in contained tungsten metal along with a very impressive 9.3% increase in contained molybdenum."
"The inclusion of copper in the Molyhil Mineral Resource further enhances the potential of this project as we work toward a project financing package for Molyhil".
"While the copper grades in the Molyhil Mineral Resource are modest, the copper minerals are extracted as a by-product of the molybdenum and other sulphide products flotation stage without additional reagent addition, and virtually therefore at no additional cost".
In recognition of consistent recoveries of copper in process testwork on Molyhil ore samples, Thor Mining commissioned mining consultants RPM Global to review the Mineral resource Estimate for Molyhil to establish if the resource estimate could be augmented accordingly. The revised estimate is based upon no new sample data other than for these historical copper intersections.
The Mineral Resource for the Molyhil deposit is reported at a cut-off grade of 0.12% tungsten equivalent and above an elevation of 200m RL as at 18(th) September, 2019. Readers should note that the Mineral Resource has an applied grade adjustment factor for the RC drilling assays. The adjustment factor is supported by review of RC tungsten and molybdenum assays compared to underground bulk samples, diamond core samples and recent metallurgical hole core samples.
Although the adjustment factor has been applied, the reader should note there are a number of risks associated with it that should be further investigated and their impact reduced or mitigated before proceeding with classification of confidence categories higher than an Indicated Mineral Resource, any higher confidence economic evaluation of the deposit or progression to a feasibility study.
Table A: Molyhil Summary JORC (2012) Mineral Resource Estimate As At 18(th) September, 2019
Hot Features
Premium
Classification Resource WO(3) Mo Cu Fe
'000 Grade Tonnes Grade Tonnes Grade Tonnes Grade
Tonnes % % % %
---------------- --------- ----- ------ ----- ------- ----- ------ ------
Indicated 3,780 0.29 11,000 0.14 5,400 0.05 1,800 18.7
Inferred 930 0.25 2,300 0.15 1,400 0.04 300 15.2
--------- ----- ------ ----- ------- ----- ------ ------
Total 4,710 0.28 13,300 0.14 6,800 0.05 2,200 18.0
--------- ----- ------ ----- ------- ----- ------ ------
Notes:
-- Thor Mining PLC holds 100% equity interest in this project.
-- The Mineral Resource is reported at 0.12% WO(3) equivalent cut-off and above 200mRL only on a dry, in-situ basis
-- The Statement of Estimates of Mineral Resources has been compiled by Mr. David Allmark who is a full-time employee of RPM and a Member of the AIG. Mr. Allmark has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity that he has undertaken to qualify as a Competent Person as defined in the JORC Code (2012).
-- All Mineral Resource figures reported in the table above represent estimates as at 18th September, 2019. Mineral Resource estimates are not precise calculations, being dependent on the interpretation of limited information on the location, shape and continuity of the occurrence and on the available sampling results.
-- Mineral Resources are reported in accordance with the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (The Joint Ore Reserves Committee Code - JORC 2012 Edition).
-- The totals contained in the above table have been rounded to reflect the relative uncertainty of the estimate. Rounding may cause some computational discrepancies.
-- The Mineral Resource was reported by a WO(3) equivalence defined by the following formula:
WO(3) eq = WO(3) + 0.952658*Mo + 0.298054*Cu
-- Reporting cut-off grade was selected by RPM based on parameters defined by an Ore Reserve update in 2017 and RPM's experience in these types of deposits.
-- To satisfy the criteria of reasonable prospects for eventual economic extraction, the Mineral Resources have been reported down to 200m RL which defines material that could be potentially extracted using open pit mining methods.
-- The Company is not aware of any information or data which would materially affect the Mineral Resource, and all assumptions and key technical parameters relevant to the previous estimate remain unchanged, with the exception of the addition of copper to the current Mineral Resource.
Summary of Mineral Resource Estimate and Reporting Criteria
The Molyhil resource area extends over a strike length of 250m and includes 410m of vertical extent from 410mRL to 0mRL. Cross-sectional geological interpretations have been undertaken on a 15 to 25m section spacing to match drilling lines. The deposit consists of two adjacent outcropping iron rich skarn bodies, marginal to a granite intrusion, that contain scheelite (tungsten mineralisation as CaWO(4) ) and molybdenite (molybdenum as MoS(2) ) mineralogy. Both the outlines of, and the banding within the skarn bodies, strike approximately north-south and dip steeply to the east. The bodies are arranged in an en-echelon manner, the northeast body being named the Yacht Club and the southwest body the Southern.
Drill holes used in the resource estimate included 82 surface RC holes (11,947m), 15 surface diamond holes (1,816m) and three underground exploration shafts and cross-cuts (198m). Prospect drilling prior to 2004, water bores and RAB holes were not used in the estimation of the Mineral Resource.
The most recent site visit was conducted by Mr Craig Allison and Mr Joe McDiarmid of RPM in October 2011. The site visit was undertaken with Mr Richard Bradey, Exploration Manager for Thor. Historical mining areas and drill holes were inspected and are spatially similar to localities plotted on company maps. The site visit review concluded current geological models are supported by drilling and that drill data collection to the date of the site visit has been undertaken to industry standards. RPM and its CP understand through communication with Thor that no additional mining activities have occurred with only limited exploration since the previously reported Mineral Resource. As such, no site visit was considered necessary for this Mineral Resource update.
Hole collars were accurately surveyed by DGPS by qualified surveyors during the 2011 drill campaign. Down hole re-surveying of previous drilling has also been undertaken using a north-seeking gyro instrument and identified that a minor azimuth correction of +8 degrees should be applied to non-surveyed holes.
Samples were collected mainly at 1m intervals with some variation to account for barren hanging-wall zones and geological boundaries. Samples were assayed for iron (Fe), molybdenum (Mo), tungsten (W) and copper (Cu) using the XRF assay method.
Quality control data was available for the drilling programs by Thor and included a comprehensive program of certified standards, blanks and duplicates. The combined diamond/ RC quality assurance results are within acceptable limits for iron, however some widely scattered field duplicate results for molybdenum, tungsten and copper can be observed. Of significance when the QAQC data is separated by drilling type, the RC field duplicates show higher repeatability than the diamond core samples, which would be expected for the mineralisation style and the smaller sample size of the diamond core. While this shows suitable repeatability of the sample from the cyclone of the RC sample, the twin holes completed with diamond core show significant variation which questions the precision accuracy of the RC sample assays. It is noted that the diamond core holes have >95% recovery within the mineralised zones whereas recovery was not recorded for all RC samples and previous reports have commented on some low recoveries within the mineralised zones.
Given the issues noted, a further review was undertaken of the grade adjustment factor applied to the molybdenum and tungsten RC drill samples in the previous Mineral Resource reported. It is noted that this review was completed by comparing the sample data from the 2005 near-surface underground workings, 2011 twin diamond drill holes and metallurgical diamond core holes. This updated review (including a complete review of the QAQC samples) interpreted that the coarse-grained, brittle and heterogeneous nature of the mineralisation, as confirmed by underground mapping, could result in a likely sample bias for the RC assays of tungsten and molybdenum compared to the interpreted more representative underground bulk and diamond core samples. It is considered this bias is due to excessive partitioning of both scheelite and molybdenite material into the outside return air stream during the RC drilling procedure, which could result in an excessive loss (>15%) of fine particles and a corresponding reduction in grade of tungsten and molybdenum of the sample. It was also noted from the 1,000 tonne bulk sampling program that higher grade molybdenum material was softer and produced more fine material than harder, barren material when crushed as would be the case during RC drilling. Pilot holes drilled by RAB drilling rigs also noted poor sample quality and low recoveries.
The analysis concluded the previous adjustment factor of 114% molybdenum and 144% tungsten was still applicable from surface down to 350mRL pending further information. Below the 350mRL an adjustment factor of 144% for molybdenum and no change to tungsten was applied. The adjustment factor was applied to tungsten and molybdenum RC assays only and no other changes were applied to the assays.
It is noted there are a number of risks associated with the use of a grade adjustment factor which include that the analysis may not be representative of all areas of the deposit and that the number of twin drill holes chosen (six) was insufficient or not representative. Additionally, the metallurgical test holes, although of imprecise location, appear to indicate limited support for the Mo adjustment factor but strong support for the WO(3) adjustment factor. The January 2012 Mineral Resource acknowledged these risks as being a major factor in applying the Indicated confidence category to the more well-informed portion of the deposit. This is re-confirmed in the current estimate.
Following the amendments to the database, assay grade, lithology and structure were used to define the margins of the mineralised zones. Wireframes of the mineralisation were constructed using cross sectional interpretations based on a nominal 10 to 15% iron oxide cut-off grade with a minimum downhole length of 2m. This iron cut-off grade broadly corresponds to the skarn boundary within which the majority of the scheelite and molybdenite mineralisation is located. Minor mineralisation adjacent to the skarn bodies was also incorporated into the mineralisation wireframe which did not correspond to the iron cut off. It was not considered necessary to include an additional domain given the immateriality of the mineralisation outside of this Fe boundary and metallurgical differences with this material.
Samples within the wireframes were composited to 1m intervals based on analysis of the sample lengths in the database and the width of mineralisation zones. Tungsten (W) assays were converted to WO(3) for the purpose of estimation and reporting. High grade element cuts of 2% for Mo, between 6% and 9% for WO(3) and 0.4% for Cu were applied to the corresponding composites within the mineralisation domain after statistical analysis. No high grade cut was applied to the iron assay grades.
A Surpac block model was used for the estimate with a block size of 10m N by 5m E and 5m in elevation with sub-cells of 2.5m by 1.25m by 1.25m. No rotation was applied to the block model as the overall strike of mineralisation is north-south. Ordinary Kriging interpolation with an oriented 'ellipsoid' search was used for the estimate of each element. The ellipse was oriented to match mineralisation trends and is based on the variogram models.
For the iron (Fe) estimate, a first pass search radius of 40m and a second pass search radius of 100m were used with a minimum number of samples of 20 and a maximum of 26 for all objects in the first pass. Approximately 45% of the blocks were filled in the first estimation pass and 53% of the blocks were filled in the second estimation pass. A third estimation pass of 200m search radius was used to fill remaining un-estimated model blocks.
For the molybdenum (Mo) estimate, a first pass search radius of 40m and a second pass search radius of 90m were used with a minimum number of samples of 20 and a maximum of 32 for all domains in the first pass. Approximately 27% of the blocks were filled in the first estimation pass and 66% of the blocks were filled in the second estimation pass. A third estimation pass of 300m search radius was used to fill remaining un-estimated model blocks.
For the tungsten oxide (WO(3) ) estimate, a first pass search radius of 30m and a second pass search radius of 60m were used with a minimum number of samples of 20 and a maximum of 32 for all objects in the first pass. Approximately 33% of the blocks were filled in the first estimation pass and 60% of the blocks were filled in the second estimation pass. A third estimation pass of 250m search radius was used to fill remaining un-estimated model blocks.
A bulk density value for the block model was derived from an iron (Fe) - bulk density regression equation. A total of 69 bulk density measurements have been taken from the 2004 drilling campaign and a strong association between increasing iron grade and bulk density is recognised. The equation of the regression line was applied to the mineralisation domain only. An average bulk density value of 2.75t/m(3) was used for the barren background domain. A bulk density of 2.0 t/m3 was used for the historical stockpile material adjacent to the mined area.
The reader should note that a grade adjustment factor was applied to the data which underpins the Mineral Resource as the review indicated there was evidence of a sampling bias caused by unsuitable RC drilling methods for the mineralisation style. RPM and its CP recommends work should be undertaken to further confirm and accurately quantify the grade adjustment factor and to reduce or mitigate the associated risks. This work would consist of duplication of selected RC holes with additional equipment to settle and collect the material in the outside return for assay, and drilling of a set of around thirty diamond holes in locations spread evenly throughout the deposit; to be used to more representatively investigate and quantify the grade adjustment factor prior to improving the Mineral Resource classification to the Measured category in the more well-informed areas, or proceeding to higher confidence economic evaluation of the deposit or feasibility studies for development of the Project.
The Mineral Resource was classified on the basis of sample spacing, continuity of the interpreted zones and geostatistical measurement of estimation errors and potential risks associated with the application of the grade adjustment factor. In general, zones where drill hole spacing was in the order of 30m by 40m or less and reasonable continuity was apparent, supported by bulk samples and twin holes were classified as Indicated Mineral Resource. Those zones, where drill hole spacing was greater than 30m by 40m, or where the continuity and/or geometry were uncertain were classified as Inferred Mineral Resource. No areas were classified as Measured after considering the precision of the molybdenum and tungsten adjustment factor analysis and drill spacing. Mineralised areas below the 200m RL were not classified as further work is required to determine economic grade cut-offs below this level.
The Mineral Resource has been reported at a tungsten equivalent cut-off grade of 0.12% WO(3) equivalent and above an elevation of 200m RL to report potentially economic material. The tungsten equivalent was determined using the prices and recoveries of tungsten, molybdenum and copper as determined from RPM's review and from test work. The WO(3) equivalent was determined by the following formula:
WO(3) equivalent = WO(3) + 0.952658*Mo + 0.298054*Cu
Prices and recoveries of USD22,400/t and 79% for WO(3) , USD23744/t and 71% for Mo and USD7644/t and 69% for Cu respectively, were used to determine the WO(3) metal equivalent formula.
To report material that has reasonable prospects for economic extraction by open pit mining methods, RPM used a cut-off grade of 0.12% WO(3) equivalent. The cut-off grade was determined using 10% ore loss and 5% dilution, tungsten recovery of 79% and a tungsten concentrate grade of 62%. The Mineral Resource was reported above this WO(3) equivalent cut-off grade and above the 200m RL level.
The information contained within this announcement is deemed to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014. Upon the publication of this announcement, this inside information is now considered to be in the public domain.
Enquiries:
Mick Billing +61 (8) 7324 Thor Mining PLC Executive Chairman
1935
Ray Ridge +61 (8) 7324 Thor Mining PLC CFO/Company
1935 Secretary
Colin Aaronson/ +44 (0) 207 383 Grant Thornton UK Nominated Adviser
Richard Tonthat/ Ben 5100 LLP
Roberts
Nick Emerson +44 (0) 1483 SI Capital Ltd Joint Broker
Claire Louise Noyce 413 500 Hybridan LLP Joint Broker
/ +44 (0) 203 764
John Beresford-Peirse 2341
Updates on the Company's activities are regularly posted on Thor's website www.thormining.com, which includes a facility to register to receive these updates by email, and on the Company's twitter page @ThorMining.
Competent Person's Report
The estimates of Mineral Resources presented in this release have been carried out in accordance with the "Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves" (The JORC Code - 2012 Edition).
The information in this release that relates to Mineral Resources is based on information compiled by Mr David Allmark who is a Member of the Australian Institute of Geoscientists and a full-time employee of RPM. Mr Allmark is the Competent Person for this Mineral Resource estimate and has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he has undertaken to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for the Reporting of Exploration Results, Mineral Resources and Ore Reserves'.
Mr Allmark has no economic, financial or pecuniary interest in Thor and is not aware of any potential for a conflict of interest in relation to this work for Thor.
About Thor Mining PLC
Thor Mining PLC (AIM, ASX: THR) is a resources company quoted on the AIM Market of the London Stock Exchange and on ASX in Australia.
Thor holds 100% of the advanced Molyhil tungsten project in the Northern Territory of Australia, for which an updated feasibility study in August 2018(1) suggested attractive returns.
Adjacent Molyhil, at Bonya, Thor holds a 40% interest in deposits of tungsten, copper, and vanadium, including an Inferred resource for the Bonya copper deposit(2).
Thor also holds 100% of the Pilot Mountain tungsten project in Nevada USA which has a JORC 2012 Indicated and Inferred Resources Estimate(3) on 2 of the 4 known deposits. The US Department of the Interior has confirmed that tungsten, the primary resource mineral at Pilot Mountain, has been included in the final list of Critical Minerals 2018.
Thor is also acquiring up to a 30% interest Australian copper development company EnviroCopper Limited, which in turn holds rights to earn up to a 75% interest in the mineral rights and claims over the resource on the portion of the historic Kapunda copper mine in South Australia recoverable by way of in situ recovery , and also holds rights to earn a 75% interest in portion of the Moonta Copper project also in South Australia, and is considered amenable to recovery by way of in situ recovery .
Thor has an interest in Hawkstone Mining Limited, an Australian ASX listed company with a 100% Interest in a Lithium project in Arizona, USA.
Finally, Thor also holds a production royalty entitlement from the Spring Hill Gold project of:
-- A$6 per ounce of gold produced from the Spring Hill tenements, sold for up to A$1,500 /oz; and
-- A$14 per ounce of gold produced from the Spring Hill tenements, sold for amounts over A$1,500 /oz.
Notes
(1) Refer ASX and AIM announcement of 23 August 2018
(2) Refer ASX and AIM announcement of 26 November 2018
(3) Refer AIM announcement of 13 December 2018 and ASX announcement of 14 December 2018
Refer AIM announcement of 10 February 2016 and ASX announcement of 12 February 2018
Refer AIM announcement of 5 March 2019 and ASX announcement of 6 March 2019
Mr Richard Bradey, Exploration Manager for Thor compiled the information in Section 1 and Section 2 of JORC Table 1 in this Mineral Resource report and is the Competent Person for those sections. David Allmark is the Competent Person for Section 3. RPM has included these sections in their entirety to ensure that all relevant sections of Table 1 are included in this report. RPM has added some additional commentary associated with the grade adjustment factor applied to the Mineral Resource.
Section 1 Sampling Techniques and Data
Criteria JORC Code explanation Commentary
------------- ---------------------------------------------------------------------- ------------------------------------------------------------
Sampling
techniques * Nature and quality of sampling (eg cut channels, * The mineralised lodes at the Molyhil deposit were
random chips, or specific specialised industry sampled using surface diamond drill holes, percussion
standard measurement tools appropriate to the holes, and underground shaft and cross-cut bulk
minerals under investigation, such as down hole gamma sampling. Drilling was conducted primarily on nominal
sondes, or handheld XRF instruments, etc). These 25m by 25m line spacing, reduced in areas to 12.5m by
examples should not be taken as limiting the broad 12.5m and drilled on the GDA94 National Grid system.
meaning of sampling.
* Three winzes (2m x 1.2m) totalling 96m and three
cross-cuts (2.1m x 1.2m) totalling 102m were sunk
into the orebody. The winzes and cross-cuts were all
sampled at 2m intervals.
* Drill holes used in the resource estimate included 15
diamond holes, 89 percussion holes, and 3 underground
shafts with associated cross-cuts for a total of
14,906.9m within the resource wireframes. The
supplied database contained a total of 162 drill hole
records for a total of 19,163.25m of drilling. Holes
* Include reference to measures taken to ensure sample were generally angled at -60deg towards the west
representivity and the appropriate calibration of any (average of 252deg azimuth) to optimally intersect
measurement tools or systems used. the mineralised zones.
* All accessible drill hole collars and starting
azimuths and downhole deviations were accurately
re-surveyed by Direct Systems surveyors in 2011. Dip
and azimuth values were measured at 10m intervals
* Aspects of the determination of mineralisation that down hole using North Seeking Gyro equipment.
are Material to the Public Report. In cases where
'industry standard' work has been done this would be
relatively simple (eg 'reverse circulation drilling * Drilling was conducted by Petrocarb, Tennant Creek
was used to obtain 1 m samples from which 3 kg was Gold and by Thor. Petrocarb drilling prior to 2005
pulverised to produce a 30 g charge for fire assay'). was not included in the data used for the Mineral
In other cases more explanation may be required, such Resource Estimate. Diamond drilling used a 63.5mm
as where there is coarse gold that has inherent core diameter (HQ) with sampling at varying intervals
sampling problems. Unusual commodities or based on geological boundaries. Half-split core was
mineralisation types (eg submarine nodules) may sampled and sent for analysis. RC drilling used a 5"
warrant disclosure of detailed information. face sampling bit, a cyclone and an industry standard
riffle splitter. All samples were sent for
preparation (crushing and pulverising) and analysed
using the XRF method at various laboratories
including ALS Perth, Amdel Adelaide and Genalysis
Perth.
---------------------------------------------------------------------- ------------------------------------------------------------
Drilling
techniques * Drill type (eg core, reverse circulation, open-hole * Diamond or percussion drilling were the primary
hammer, rotary air blast, auger, Bangka, sonic, etc) techniques used at Molyhil. Diamond holes make up 12%
and details (eg core diameter, triple or standard of the total metres drilled with a core diameter of
tube, depth of diamond tails, face-sampling bit or 63.5mm. Hole depths ranged from 55m to 207m.
other type, whether core is oriented and if so, by Percussion drilling makes up 88% of the total holes
what method, etc). drilled with depths ranging from 12m to 502m. Shaft
or cross-cut sampling accounts for less than 1% of
sample results in the database.
---------------------------------------------------------------------- ------------------------------------------------------------
Drill sample
recovery * Method of recording and assessing core and chip * Recoveries from diamond core were only recorded when
sample recoveries and results assessed. there was significant core loss, examination of the
photographs of the core trays indicates that overall
recovery was very good. All diamond core was oriented
where possible.
* Measures taken to maximise sample recovery and ensure
representative nature of the samples. * Diamond core was reconstructed into continuous runs
for orientation marking with depths checked against
core blocks.
* Most percussion samples were visually checked for
recovery and moisture content and the data recorded.
* Whether a relationship exists between sample recovery The recorded recovery figures averaged 84%, with most
and grade and whether sample bias may have occurred samples recorded as being dry.
due to preferential loss/gain of fine/coarse
material.
* No relationship was noted between recorded sample
recovery and grade, however comparison of RC assays
for tungsten and molybdenum with underground bulk
sampling and diamond core indicates there may be a
reduction in RC sample grades of tungsten and
molybdenum due to excessive partitioning of both
scheelite and molybdenite material into the outside
return. It was also noted from the bulk sampling
program completed by Thor in 2006 that higher grade
molybdenum ore was softer and produced more fine
material than harder, barren material. Pilot holes
drilled by RAB drilling rigs also noted poor sample
quality and low recoveries. This sampling bias due to
preferential loss of fine material has likely
resulted in a corresponding reduction in grade of
tungsten and molybdenum of the sample.
---------------------------------------------------------------------- ------------------------------------------------------------
Logging
* Whether core and chip samples have been geologically * All holes were field logged by company geologists to
and geotechnically logged to a level of detail to a high level of detail.
support appropriate Mineral Resource estimation,
mining studies and metallurgical studies.
* Although the core was oriented it was not routinely
logged for RQD, or number and type of defects. The
supplied database contained tables with some
information vein shearing and vein percent with
* Whether logging is qualitative or quantitative in observations but no alpha/beta angles, dips, azimuths
nature. Core (or costean, channel, etc) photography. ,
and true dips.
* All drill samples were logged for lithology, rock
* The total length and percentage of the relevant type, colour, mineralisation, alteration, and
intersections logged. texture. Logging is a mix of qualitative and
quantitative observations. It has been standard
practice by Thor (since 2005), that all diamond core
be routinely photographed.
* All drill holes were logged in full.
---------------------------------------------------------------------- ------------------------------------------------------------
Sub-sampling
techniques * If core, whether cut or sawn and whether quarter, * Diamond core was cut in half using a core saw with
and sample half or all core taken. half core submitted for assay.
preparation
-- * Percussion drill samples were collected at 1m
* If non-core, whether riffled, tube sampled, rotary intervals. Samples were collected at the drilling rig
split, etc and whether sampled wet or dry. and split with a riffle splitter at the drill site.
Samples were predominantly dry. Drilling was through
bedrock from surface. Sampling of diamond core and RC
chips used industry standard techniques.
* For all sample types, the nature, quality and
appropriateness of the sample preparation technique.
* Thor has used systematic standard and pulp duplicate
sampling since 2005. Detailed data from the 2011
program indicates that a sequence of every 25(th)
sample was submitted as a standard, a different
* Quality control procedures adopted for all sequence of every 25(th) sample was inserted as a
sub-sampling stages to maximise representivity of field duplicate and a third sequence of every 25(th)
samples. sample was inserted as a blank. This resulted in 3
samples in every 25 being a QAQC sample
(approximately 12% of all samples).
* Measures taken to ensure that the sampling is
representative of the in situ material collected,
including for instance results for field * Sample sizes (3-5kg for core and 2-5kg for chips) are
duplicate/second-half sampling. considered appropriate to correctly represent the W
and Mo mineralisation based on: the style of
mineralisation, the thickness and consistency of the
intersections, the sampling methodology and assay
* Whether sample sizes are appropriate to the grain value ranges for W and Mo.
size of the material being sampled.
---------------------------------------------------------------------- ------------------------------------------------------------
Quality of
assay data * The nature, quality and appropriateness of the * The assay method used for all drill samples was XRF.
and assaying and laboratory procedures used and whether The lower detection limit is in the order of 0.01% to
laboratory the technique is considered partial or total. 0.005% for Fe or 0.005% to 0.0001% for Mo or W and
tests well within the level of accuracy or grade cut-off
required for the resource estimate.
* For geophysical tools, spectrometers, handheld XRF * No geophysical tools were used to determine any
instruments, etc, the parameters used in determining element concentrations used in this resource
the analysis including instrument make and model, estimate.
reading times, calibrations factors applied and their
derivation, etc.
* The various programs of QAQC carried out by Thor over
the years have produced results which support the
* Nature of quality control procedures adopted (eg sampling and assaying procedures used at the various
standards, blanks, duplicates, external laboratory deposits..
checks) and whether acceptable levels of accuracy (ie
lack of bias) and precision have been established.
* A total of 6 different certified reference materials
representing a variety of grades from 0.12% to 0.28%
for W and 0.09% to 0.48% for Mo were inserted
regularly during the 2011 drilling program for a
total of 67 samples. Results highlighted that the
sample assays are within accepted values, showing no
obvious bias.
* A total of 88 blank samples were submitted during the
2011 drill program and results show that sample
contamination has been mostly contained.
* Field duplicate analyses (a total of 68) mostly
honour the original assay for Fe however show some
widely scattered field duplicate results for W, Mo
and Cu indicating a high natural grade variability.
---------------------------------------------------------------------- ------------------------------------------------------------
Verification
of sampling * The verification of significant intersections by * RPM has independently verified significant
and assaying either independent or alternative company personnel. intersections of mineralisation. The 2011 site visit
inspected 2011 drill core and noted similar
identification of geological features. Resource
* The use of twinned holes. mineralisation outlines were agreed upon by RPM and
Thor geologists.
* Documentation of primary data, data entry procedures, * Analysis of twinned RC vs. diamond holes and RC vs.
data verification, data storage (physical and underground cross-cuts (bulk samples) has identified
electronic) protocols. there is a reduction in RC sample grade for W and Mo.
RPM considers that excessive partitioning of both
scheelite and molybdenite material into the outside
return air stream during the RC drilling procedure
* Discuss any adjustment to assay data. could result in a reduction in grade of tungsten and
molybdenum of the sample. It was also noted from the
bulk sampling program that higher grade molybdenum
ore was softer and produced more fine material than
harder, barren material. Pilot holes drilled by RAB
drilling rigs also noted poor sample quality and low
recoveries.
* RPM conducted reviews of all the available data that
could be related to the application of a grade
adjustment factor for the RC drill hole data. The
adjustment factors used for the resource estimate
were updated for the January 2012 Mineral Resource
estimate. This was reviewed again for the 2019 update
and additional recommendations to improve the number
and coverage of twin diamond holes were made to be
completed prior to any further economic evaluation of
the deposit including more advanced feasibility
studies.
* Due to this reduction in grade RPM considered it
appropriate that Mo and W grade adjustment factors
should be applied. An adjustment factor of 114% for
Mo and 144% for W above the 350m RL level and 144%
for Mo and no change for W below the 350m RL level
was applied prior to grade estimation. The grade
adjustment factor was applied to tungsten and
molybdenum RC assays only and no other changes were
applied to the assays
---------------------------------------------------------------------- ------------------------------------------------------------
Location of
data points * Accuracy and quality of surveys used to locate drill * Drill hole collars and starting azimuths have been
holes (collar and down-hole surveys), trenches, mine accurately re-surveyed by independent surveyors using
workings and other locations used in Mineral Resource a DGPS instrument. Down hole dip values and azimuths
estimation. were recorded at 10m intervals using digital
equipment such as a north-seeking gyro instrument.
* Drill hole locations were positioned using the MGA
Grid System.
* Specification of the grid system used. * The topographic surface over the Molyhil deposit was
provided to RPM by Thor. Drill hole collars have been
used to create a more accurate surface immediately
above the mineralised lodes.
* Quality and adequacy of topographic control.
---------------------------------------------------------------------- ------------------------------------------------------------
Data spacing
and * Data spacing for reporting of Exploration Results. * Drill holes have been located at 25m by 25m
distribution throughout the mineralised lodes at Molyhil, and
mainly drilled steeply westward to intersect steeply
* Whether the data spacing and distribution is east-dipping, moderately south-plunging skarn bodies.
sufficient to establish the degree of geological and Some broader spaced drilling has been undertaken away
grade continuity appropriate for the Mineral Resource from near-surface mineralisation.
and Ore Reserve estimation procedure(s) and
classifications applied.
* The main mineralised domains have demonstrated
sufficient continuity in both geological and grade
* Whether sample compositing has been applied. continuity to support the definition of Mineral
Resource, and the classifications applied under the
2012 JORC Code.
* Data density is sufficient to define reasonably
structured variograms for each element.
* Samples have been composited to 1m lengths using
'best fit' techniques.
---------------------------------------------------------------------- ------------------------------------------------------------
Orientation
of data in * Whether the orientation of sampling achieves unbiased * Drill holes are orientated predominantly to an
relation to sampling of possible structures and the extent to azimuth of 252deg and drilled at an angle of -60deg
geological which this is known, considering the deposit type. to the west which is approximately perpendicular to
structure the orientation of the mineralised trends.
* If the relationship between the drilling orientation
and the orientation of key mineralised structures is * The orientation of the drilling is at a high angle to
considered to have introduced a sampling bias, this the strike and dip of the mineralisation and is
should be assessed and reported if material. unlikely to have introduced any sampling bias due to
orientation.
---------------------------------------------------------------------- ------------------------------------------------------------
Sample
security * The measures taken to ensure sample security. * No information has been provided to RPM with respect
to the sample security for historical drilling.
---------------------------------------------------------------------- ------------------------------------------------------------
Audits or
reviews * The results of any audits or reviews of sampling * A review of sampling techniques and data was carried
techniques and data. out during a site visit conducted in October 2011.
The conclusion was that sampling and data capture was
to industry standards.
---------------------------------------------------------------------- ------------------------------------------------------------
Section 2 Reporting of Exploration Results
Criteria JORC Code explanation Commentary
--------------- ---------------------------------------------------------------- -----------------------------------------------------------------
Mineral
tenement and * Type, reference name/number, location and ownership * The tenements at Molyhil comprise EL22349, ML23825,
land tenure including agreements or material issues with third ML24429 and ML25721. For all tenements Thor Mining
status parties such as joint ventures, partnerships, PLC hold 100% Project Equity.
overriding royalties, native title interests,
historical sites, wilderness or national park and
environmental settings. * Thor has completed the Public Environmental Report
for the Molyhil Tungsten and Molybdenum Project. This
report has been accepted by the Department of
* The security of the tenure held at the time of Regional Development, Primary Industry, Fisheries and
reporting along with any known impediments to Resources in the Northern Territory
obtaining a license to operate in the area.
* This report was approved on the 15th July 2007 by the
DRDPIFR (NT), who also confirmed in December 2011
that the approval remains current. The report is
available on request.
* Thor Mining PLC has also obtained all the required
agreements between the Traditional Owners of the land,
and Thor Mining PLC, to enable the Molyhil Operations
to proceed with the recognition and support of the
Traditional Owners.
* The Tripartite Deed records the terms of the
Agreement between the parties in accordance with the
Native Title Act and is between the Arrapere People,
the Central Land Council and Thor Mining PLC.
* There are no known impediments to obtaining a licence
to operate in the area.
---------------------------------------------------------------- -----------------------------------------------------------------
Exploration
done by other * Acknowledgment and appraisal of exploration by other * Tungsten and molybdenum mineralisation was originally
parties parties. discovered at Molyhil in 1973. The Molyhil deposit
was initially drilled in 1977 with further drilling
carried out in 1981. The work was carried out by Fama
Mines Pty Ltd, Petrocarb NL, Nicron resources NL and
Geopeko. Between 1975 and 1976 approximately 20kt of
molybdenum and tungsten mineralisation were mined
from the northern Yacht Club skarn body.
Approximately 900kt of material was mined from the
adjacent Southern skarn body during 1978 to 1982, to
a depth of approximately 25m.
---------------------------------------------------------------- -----------------------------------------------------------------
Geology
* Deposit type, geological setting and style of * The Molyhil deposit consists of two adjacent
mineralisation. outcropping iron rich skarn bodies, marginal to a
granite intrusion, that contain scheelite (tungsten
mineralisation as CaWO4) and molybdenite (molybdenum
as MoS2) mineralogy. Both the outlines of, and the
banding within, the skarn bodies strike approximately
north-south and dip steeply to the east. The bodies
are arranged in an en-echelon manner, the northeast
body being named the Yacht Club and the southwest
body the Southern.
---------------------------------------------------------------- -----------------------------------------------------------------
Drill hole
information * A summary of all information material to the * A complete table of all relevant drill holes is
under-standing of the exploration results including a attached to the Mineral Resource report as Appendix
tabulation of the following information for all B.
Material drill holes:
* Mining and drilling information prior to 2004, water
* easting and northing of the drill hole collar bore and RAB drilling assay results were excluded
from the resource estimate. This reflected concerns
relating to the completeness and accuracy of
* elevation or RL (Reduced Level - elevation above sea historical information and the quality of RAB drill
level in metres) of the drill hole collar samples.
* dip and azimuth of the hole * In the opinion of Thor, material drill results have
been adequately reported previously to the market as
required under the reporting requirements of the ASX
* down hole length and interception depth Listing Rules.
* hole length
* If the exclusion of this information is justified on
the basis that the information is not Material and
this exclusion does not detract from the
understanding of the report, the Competent Person
should clearly explain why this is the case.
---------------------------------------------------------------- -----------------------------------------------------------------
Data
aggregation * In reporting Exploration Results, weighting averaging * Exploration results are not being reported.
methods techniques, maximum and/or minimum grade truncations
(e.g. cutting of high grades) and cut-off grades are
usually Material and should be stated.
* Where aggregate intercepts incorporate short lengths
of high grade results and longer lengths of low grade
results, the procedure used for such aggregation * Not relevant.
should be stated and some typical examples of such
aggregations should be shown in detail.
* The assumptions used for any reporting of metal
equivalent values should be clearly stated.
* A tungsten metal equivalent value was used as a
cut-off grade for the reporting of potentially
economic material. The tungsten equivalent was
determined using the prices and recoveries of
tungsten, molybdenum and copper as determined from
RPM's review and from test work.
* The WO(3) equivalent was determined by the following
formula:
WO(3) equivalent = WO(3) + 0.952658*Mo + 0.298054*Cu
* Prices and recoveries of USD22,400/t and 79% for
WO(3) , USD23744/t and 71% for Mo and USD7644/t and
69% for Cu respectively were used to determine the
WO(3) metal equivalent formula.
---------------------------------------------------------------- -----------------------------------------------------------------
Relationship
between * These relationships are particularly important in the * Drill holes were orientated predominantly to an
mineralisation reporting of Exploration Results. azimuth of 252deg and angled to a dip of -60deg,
widths and which is approximately perpendicular to the
intercept orientation of the mineralised trends.
lengths * If the geometry of the mineralisation with respect to
the drill hole angle is known, its nature should be
reported.
* If it is not known and only the down hole lengths are
reported, there should be a clear statement to this
effect (e.g.'down hole length, true width not
known').
---------------------------------------------------------------- -----------------------------------------------------------------
Diagrams
* Appropriate maps and sections (with scales) and * A plan showing mineralisation wireframes and drilling
tabulations of intercepts should be included for any is included in the body of the Mineral Resource
significant discovery being reported. These should report (Figure 12--1). A typical section through the
include, but not be limited to a plan view of drill main lodes is also included (Figure 12--3).
hole collar locations and appropriate sectional
views.
---------------------------------------------------------------- -----------------------------------------------------------------
Balanced
Reporting * Accuracy and quality of surveys used to locate drill * Drill hole collars and starting azimuths have been
holes (collar and down-hole surveys), trenches, mine accurately re-surveyed by independent surveyors using
workings and other locations used in Mineral Resource a DGPS instrument. Down hole dip values and azimuths
estimation. were recorded at 10m intervals using digital
equipment including a north-seeking gyro survey
instrument.
* Where comprehensive reporting of all Exploration
Results is not practicable, representative reporting
of both low and high grades and/or widths should be * Drill hole locations were positioned using the MGA
practiced to avoid misleading reporting of Grid System.
Exploration Results.
* Exploration results are not being reported.
---------------------------------------------------------------- -----------------------------------------------------------------
Other
substantive * Other exploration data, if meaningful and material, * Three winzes totalling 96m and three cross-cuts
exploration should be reported including (but not limited to): totalling 102m were excavated into the orebody.
data geological observations; geophysical survey results;
geochemical survey results; bulk samples - size and
method of treatment; metallurgical test results; bulk * Historically three trenches were excavated into the
density, groundwater, geotechnical and rock surface of the orebody.
characteristics; potential deleterious or
contaminating substances.
---------------------------------------------------------------- -----------------------------------------------------------------
Further work
* The nature and scale of planned further work (e.g. * Thor have recently completed a Feasibility Study and
tests for lateral extensions or depth extensions or further metallurgical test work.
large- scale step-out drilling).
* RPM recommends the RC grade adjustment factor be
checked by duplication of selected RC holes with
additional equipment to settle and collect the
* Diagrams clearly highlighting the areas of possible material in the outside return for assay.
extensions, including the main geological
interpretations and future drilling areas, provided
this information is not commercially sensitive. * RPM also recommends drilling a set of around thirty
diamond holes in locations spread evenly throughout
the deposit to be used to more representatively
investigate and quantify the grade adjustment factor
prior to improving the Mineral Resource
classification to Measured category or proceeding to
economic evaluation or further feasibility studies
for development of the Project.
* Increase confidence in the Inferred Resource with
infill drilling down to and below the 200m RL and at
the peripheries of current mineralised zones to allow
the definition of additional Indicated Resource and a
larger optimised pit shell for future open pit Ore
Reserve and mining studies.
---------------------------------------------------------------- -----------------------------------------------------------------
Section 3 Estimation and Reporting of Mineral Resources
Criteria JORC Code explanation Commentary
--------------- --------------------------------------------------------------- -----------------------------------------------------------------
Database
integrity * Measures taken to ensure that data has not been * Drilling data was initially captured on paper logs
corrupted by, for example, transcription or keying and manually entered into a database. Thor carried
errors, between its initial collection and its use out internal checks to ensure the transcription was
for Mineral Resource estimation purposes. error free. Laboratory assay results were loaded as
electronic files direct from the laboratory so there
was little potential for transcription errors.
* Data validation procedures used.
* The data base was systematically audited by Thor
geologists. All drill logs were validated digitally
by the database geologist once assay results were
returned from the laboratory.
* RPM also performed data audits in Surpac and checked
collar coordinates, down hole surveys and assay data
for errors. No errors were found.
--------------------------------------------------------------- -----------------------------------------------------------------
Site visits
* Comment on any site visits undertaken by the * The most recent site visit was conducted by Mr Craig
Competent Person and the outcome of those visits. Allison and Mr Joe McDiarmid of RPM in October 2011.
The site visit was undertaken with Mr Richard Bradey,
Exploration Manager for Thor. Historical mining areas
* If no site visits have been undertaken indicate why and drill holes were inspected and are spatially
this is the case. similar to localities plotted on company maps. The
site visit review concluded current geological models
are supported by drilling and that drill data
collection to the date of the site visit has been
undertaken to industry standards. RPM and its CP
understand through communication with Thor that no
additional mining activities have occurred with only
limited exploration since the previously reported
Mineral Resource. As such, no site visit was
considered necessary for this Mineral Resource
update.
--------------------------------------------------------------- -----------------------------------------------------------------
Geological
interpretation * Confidence in (or conversely, the uncertainty of) the * The Molyhil deposit consists of two adjacent
geological interpretation of the mineral deposit. outcropping iron rich skarn bodies, enclosed in
granite, that contain scheelite and molybdenite
mineralisation. Both the outlines of, and the banding
within the bodies strike approximately north south
and dip steeply to the east. The bodies are arranged
in an en-echelon manner, the northeast body being
named the Yacht Club and the southwest body the
Southern.
* The geology of the Molyhil deposit is well understood
* Nature of the data used and of any assumptions made.
* Drill hole logging by Thor geologists, through direct
observation of drill core and percussion samples have
been used to interpret the geological setting. The
bedrock is exposed by surface trenches and limited
underground openings.
* The effect, if any, of alternative interpretations on
Mineral Resource estimation.
* The continuity of the main mineralised lodes is
clearly observed by relevant grades within the drill
holes. The close spaced drilling and trench and
underground sampling suggest the current
interpretation is robust. The nature of the lodes
would indicate that alternate interpretations would
have little impact on the overall Mineral Resource
estimate.
* The use of geology in guiding and controlling Mineral
Resource estimation.
* Mineralisation is coarse-grained and its distribution
is irregular. Two broad lithological variations are
present within the skarn
* "Black rock skarn": Mineralised, selectively mined on
the basis of colour, a calc-silicate containing a
high proportion of magnetite, pyrite, and iron-rich
minerals such as andradite-garnet, actinolite, and
ferro-amphibole.
* The factors affecting continuity both of grade and * Unmineralised skarn: Pale green coloured
geology. calc-silicate, containing diopsidic pyroxene and
garnet.
* The interpretations have been useful in predicting
the continuity of the mineralisation for the Mineral
Resource estimate
--------------------------------------------------------------- -----------------------------------------------------------------
Dimensions
* The extent and variability of the Mineral Resource * The Molyhil resource area extends over a combined
expressed as length (along strike or otherwise), plan strike length of 300m from 19,850mN to 20,150mN, a
width, and depth below surface to the upper and lower width of 250m from 9,950mE to 10,200mE and includes
limits of the Mineral Resource. the vertical extent of 290m from 410mRL to 120mRL.
--------------------------------------------------------------- -----------------------------------------------------------------
Estimation and
modelling * The nature and appropriateness of the estimation * Ordinary Kriging ("OK") interpolation with an
techniques technique(s) applied and key assumptions, including oriented 'ellipsoid' search was used for the
treatment of extreme grade values, domaining, estimate. Surpac software was used for the
interpolation parameters and maximum distance of estimation.
extrapolation from data points. If a computer
assisted estimation method was chosen include a
description of computer software and parameters used. * Three dimensional mineralised wireframes were used to
domain the mineralised data. Sample data was
composited to 1m down hole lengths using the 'best
fit' method. Intervals with no assays were excluded
from the estimate.
* The availability of check estimates, previous * The influence of extreme grade values was addressed
estimates and/or mine production records and whether by reducing high outlier values by applying high
the Mineral Resource estimate takes appropriate grade cuts to the data. These cut values were
account of such data. determined through statistical analysis (histograms,
log probability plots and summary multi-variate and
bi-variate statistics) using Supervisor software.
* The assumptions made regarding recovery of
by-products.
* RPM has not made assumptions regarding recovery of
by-products from the mining and processing of the
* Estimation of deleterious elements or other non-grade Molyhil resource with the exception of copper which
variables of economic significance (eg sulphur for reports to the molybdenum concentrate.
acid mine drainage characterisation).
* No estimation of deleterious elements was carried
out. Fe, W, Mo and Cu were the major variables
* In the case of block model interpolation, the block interpolated into the block model.
size in relation to the average sample spacing and
the search employed.
* An orientated 'ellipsoid' search was used to select
data and was based on the observed lode geometry. The
search ellipse was orientated to the average strike,
plunge, and dip of the main lodes.
* Any assumptions behind modelling of selective mining
units. * Three passes were used in the estimation. For both
skarn domains, the search radii differed for each
element. For the iron (Fe) estimate, a first pass
* Any assumptions about correlation between variables. search radius of 40m and a second pass of 100m were
used with a minimum of 20 samples and a maximum of 26
samples for all objects in the first pass.
Approximately 45% of the blocks were filled in the
* Description of how the geological interpretation was first estimation pass and 53% of the blocks were
used to control the resource estimates. filled in the second estimation pass. An expanded
third estimation pass of search radius 200m was used
to fill remaining unestimated model blocks.
* For the molybdenum (Mo) estimate, a first pass search
* Discussion of basis for using or not using grade radius of 40m and a second pass of 90m were used with
cutting or capping. a minimum of 20 samples and a maximum of 32 samples
for all objects in the first pass. Approximately 27%
of the blocks were filled in the first estimation
pass and 66% of the blocks were filled in the second
estimation pass. An expanded third estimation pass of
search radius 300m was used to fill remaining
unestimated model blocks.
* The process of validation, the checking process used,
the comparison of model data to drill hole data, and * For the tungsten (WO(3) ) estimate, a first pass
use of reconciliation data if available. search radius of 30m and a second pass of 60m were
used with a minimum of 20 samples and a maximum of 32
samples for all objects in the first pass.
Approximately 33% of the blocks were filled in the
first estimation pass and 60% of the blocks were
filled in the second estimation pass. An expanded
third estimation pass of search radius 250m was used
to fill remaining unestimated model blocks.
* For the copper (Cu) estimate, a first pass search
radius of 40m and a second pass of 100m were used
with a minimum of 20 samples and a maximum of 26
samples for all objects in the first pass.
Approximately 40% of the blocks were filled in the
first estimation pass and 57% of the blocks were
filled in the second estimation pass. An expanded
third estimation pass of search radius 200m was used
to fill remaining un-estimated model blocks.
* In addition to the extraction of bulk samples from
the winzes and cross-cuts historical mining has
occurred at the Molyhil deposit. Between 1975 and
1976 approximately 20kt of molybdenum and tungsten
mineralisation was mined from the northern Yacht Club
skarn body. The adjacent Southern skarn body was
mined during 1978 to 1982 when approximately 900kt of
material (ore + waste) was extracted. A Mineral
Resource estimate was reported by RPM in January
2012.
* No assumptions were made regarding the recovery of
by-products with the exception of limited test work
results for the recovery of Cu from the molybdenum
concentrate.
* No non-grade deleterious elements were estimated.
* The parent block dimensions used were 10m NS by 5m EW
by 5m vertical with sub-cells of 2.5m by 1.25m by
1.25m. The parent block size was selected on the
basis of being approximately 40% of the average drill
hole spacing.
* No assumptions were made on selective mining units.
* Due to the independent mineralogical distribution
within each mineralised zone it was not seen as
beneficial to carry out any correlation analysis.
* The deposit mineralisation was constrained by
wireframes constructed using a 10-15% Iron Oxide
cut-off grade with a minimum intercept of 2m
required. The wireframes were applied as hard
boundaries in the estimate.
* Statistical analysis was carried out on data from
each domain. The high coefficient of variation within
some main lodes, and the scattering of high grade
outliers observed on the histograms, suggested that
high grade cuts were required if linear grade
interpolation was to be carried out. High grade
element cuts of 2% to 3% for Mo, between 6% and 11.5%
for WO(3) and 0.4% for Cu were based on statistical
analysis and were applied to the corresponding
composites within the mineralisation domain. No high
grade cut was applied to the Fe assay grades.
* A three step process was used to validate the model.
A qualitative assessment was completed by slicing
sections through the block model in positions
coincident with drilling. A quantitative assessment
of the estimate was completed by comparing the
average grades of the composite file input against
the block model output for all the resource objects.
A trend analysis was completed by comparing the
interpolated blocks to the sample composite data
within the main lodes. This analysis was completed
for intervals of northings and elevations across the
deposit. Validation plots showed good correlation
between the composite grades and the block model
grades.
--------------------------------------------------------------- -----------------------------------------------------------------
Moisture
* Whether the tonnages are estimated on a dry basis or * Tonnages and grades were estimated on a dry in situ
with natural moisture, and the method of basis. No moisture values were reviewed.
determination of the moisture content.
--------------------------------------------------------------- -----------------------------------------------------------------
Cut-off
parameters * The basis of the adopted cut-off grade(s) or quality * The nominal cut-off grade of 10-15% Fe was used to
parameters applied. define the boundaries of the skarn zones, it was
determined from analysis of log probability plots of
all samples at the deposit. This cut-off was used to
define the mineralised wireframes.
* RPM determined a WO(3) equivalent cut-off grade at
which to report the Mineral Resource above the 200m
RL level. The WO(3) equivalent was determined by the
following formula:
WO(3) eq = WO(3) + 0.952658*Mo + 0.298054*Cu
The cut-off grade at which to report the potentially
economic material was then determined
using 10% ore loss and 5% dilution and a tungsten
concentrate grade of 62% in addition to
prices and recoveries of USD22,400/t and 79% for WO3,
USD23744/t and 71% for Mo and USD7644/t
and 69% for Cu respectively.
Using the above parameters, RPM determined the economic
cut-off grade of 0.12% WO(3) equivalent.
The resulting Mineral Resource was reported above this
WO(3) equivalent cut-off grade and
above the 200m RL level.
--------------------------------------------------------------- -----------------------------------------------------------------
Mining factors
or assumptions * Assumptions made regarding possible mining methods, * The results of an independent estimate of Open Cut
minimum mining dimensions and internal (or, if Ore Reserves indicate that the deposit could
applicable, external) mining dilution. It is always potentially be mined using medium-scale open pit
necessary as part of the process of determining techniques.
reasonable prospects for eventual economic extraction
to consider potential mining methods, but the
assumptions made regarding mining methods and
parameters when estimating Mineral Resources may not
always be rigorous. Where this is the case, this
should be reported with an explanation of the basis
of the mining assumptions made.
--------------------------------------------------------------- -----------------------------------------------------------------
Metallurgical
factors or * The basis for assumptions or predictions regarding * Metallurgical and mineralogical analysis has been
assumptions metallurgical amenability. It is always necessary as conducted on drill samples taken from exploration
part of the process of determining reasonable programs. The metallurgical work has demonstrated
prospects for eventual economic extraction to successful molybdenum and tungsten recovery using a
consider potential metallurgical methods, but the combination of gravity extraction and flotation
assumptions regarding metallurgical treatment processes.
processes and parameters made when reporting Mineral
Resources may not always be rigorous. Where this is
the case, this should be reported with an explanation * Test work is currently in progress to produce a
of the basis of the metallurgical assumptions made. separate copper concentrate in addition to tungsten
(as WO(3) ) and molybdenum (as MoS(2) ) concentrates.
In the previous flowsheet, Cu reports to the
molybdenum concentrate. Work is also in progress to
optimise the flowsheet to produce cleaner
concentrates such as by the reduction of calcite. The
molybdenum cleaner tail would equate to the copper
rougher concentrate (approximately 12% copper at a
recovery of 69%) which would undergo a subsequent
cleaner stage to produce a saleable concentrate.
* The current flowsheet also incorporates optical ore
sorting after the secondary screening stage.
--------------------------------------------------------------- -----------------------------------------------------------------
Environmental
factors or * Assumptions made regarding possible waste and process * No assumptions have been made by RPM regarding
assumptions residue disposal options. It is always necessary as possible waste and process residue disposal options.
part of the process of determining reasonable
prospects for eventual economic extraction to
consider the potential environmental impacts of the
mining and processing operation. While at this stage
the determination of potential environmental impacts,
particularly for a greenfields project, may not
always be well advanced, the status of early
consideration of these potential environmental
impacts should be reported. Where these aspects have
not been considered this should be reported with an
explanation of the environmental assumptions made.
--------------------------------------------------------------- -----------------------------------------------------------------
Bulk density
* Whether assumed or determined. If assumed, the basis * The bulk density at Molyhil is mainly reflective of
for the assumptions. If determined, the method used, the magnetite content of the rock type. A regression
whether wet or dry, the frequency of the measurements, plot of iron assay and bulk density test work shows a
the nature, size and representativeness of the well correlated, generally linear relationship and
samples. covers a wide range of iron grades. The bulk density
equation presented below was also used for this
estimate. The minimum bulk density value possible
* The bulk density for bulk material must have been from the equation is 2.78 which is considered
measured by methods that adequately account for void reasonable.
spaces (vugs, porosity, etc), moisture and
differences between rock and alteration zones within
the deposit
Bulk Density = (0.0152 x converted model value Fe2O3) +
2.7826 (after Baxter & Doepel, 2006).
* Discuss assumptions for bulk density estimates used * The bulk density equation was applied to the
in the evaluation process of the different materials. mineralised lode domain as it was only this part of
the model where iron was estimated. An average bulk
density of 2.75 t/m3 was applied to the background
domain.
--------------------------------------------------------------- -----------------------------------------------------------------
Classification
* The basis for the classification of the Mineral * Mineral Resources were classified in accordance with
Resources into varying confidence categories. the Australasian Code for the Reporting of
Exploration Results, Mineral Resources and Ore
Reserves (JORC, 2012). The Mineral Resource was
classified as Indicated and Inferred Mineral Resource
on the basis of data quality, sample spacing, and
lode continuity.
* The Indicated portion of the Mineral Resource
included the area where drill hole spacing was in the
order of 30m by 40m or less and reasonable continuity
was apparent.
* Those zones where drill hole spacing was greater than
30m by 40m, or where the continuity and/or geometry
ware uncertain were classified as Inferred Mineral
* Whether appropriate account has been taken of all Resource.
relevant factors (ie relative confidence in
tonnage/grade estimations, reliability of input data,
confidence in continuity of geology and metal values, * Mineralised areas below the 200m RL were not
quality, quantity and distribution of the data). classified as further work is required to determine
economic grade cut-offs below this level (the
material is not potentially economic using open pit
mining methods).
* Whether the result appropriately reflects the * The mineralised lodes interpreted at Molyhil are
Competent Person's view of the deposit. based on a high level of geological understanding.
The drilling and sampling processes used by Thor were
'best practice' and certified laboratories have been
used for analyses of samples. The input data is
considered reliable and suitable for use in the
resource estimate.
* Analysis of twinned RC vs. diamond holes and RC vs.
underground cross-cuts (bulk samples) has identified
there is a reduction in RC sample grade for W and Mo.
RPM considers that excessive partitioning of both
scheelite and molybdenite material into the outside
return stream during the RC drilling procedure could
result in a reduction in grade of tungsten and
molybdenum of the sample. It was also noted from the
bulk sampling program that higher grade molybdenum
ore was softer and produced more fine material than
harder, barren material. Pilot holes drilled by RAB
drilling rigs also noted poor sample quality and low
recoveries. RPM conducted reviews of all the
available data that could be related to the
application of a grade adjustment factor for the RC
drill hole data. The grade adjustment factors used
for the Mineral Resource estimate were updated for
the January 2012 Mineral Resource estimate and
reviewed again for the 2019 update. Following the
review, RPM considered it appropriate that Mo and W
adjustment factors should be applied but restricted
upper confidence in the closer sampled parts of the
deposit to Indicated classification due to the
uncertainties surrounding the grade adjustment
factor. An adjustment factor of 114% for Mo and 144%
for W above the 350m RL level and 144% for Mo and no
change for W below the 350m RL level was applied
prior to grade estimation.
* RPM recommends the confidence in the RC grade
adjustment factors be further increased by
duplication of selected RC holes with additional
equipment to settle and collect the material in the
outside return air stream for assay.
* RPM also recommends drilling a set of around thirty
diamond holes in locations spread evenly throughout
the deposit to be used to more representatively
investigate and quantify the grade adjustment factors
prior to improving the classification to the Measured
category in the more well-informed areas or
proceeding to economic evaluation or further
feasibility studies for development of the Project.
* The Mineral Resource estimate appropriately reflects
the view of the Competent Person.
--------------------------------------------------------------- -----------------------------------------------------------------
Audits or
reviews * The results of any audits or reviews of Mineral * Internal audits have been completed by RPM which
Resource estimates. verified the technical inputs, methodology,
parameters and results of the estimate.
* A review of the input data, estimation methods and
results was conducted by RPM in December 2013 and
September 2019, to ensure compliance with the JORC
Code 2012.
--------------------------------------------------------------- -----------------------------------------------------------------
Discussion of
relative * Where appropriate a statement of the relative * The relative accuracy of the Mineral Resource
accuracy/ accuracy and confidence level in the Mineral Resource estimate is reflected in the reporting of the Mineral
confidence estimate using an approach or procedure deemed Resource as per the guidelines of the 2012 JORC Code
appropriate by the Competent Person. For example, the and the classification categories applied. RPM has
application of statistical or geostatistical not classified any Measured Resources due to
procedures to quantify the relative accuracy of the uncertainty around the accurate definition of the RC
resource within stated confidence limits, or, if such assay grade adjustment factor. As there is evidence
an approach is not deemed appropriate, a qualitative for a grade adjustment factor, RPM has applied the
discussion of the factors that could affect the factor to the underlying assay data and prior to
relative accuracy and confidence of the estimate. reporting the Mineral Resource with the
recommendation that further work be conducted to
confirm and accurately quantify the grade adjustment
* The statement should specify whether it relates to factor. RPM recommends the RC grade adjustment factor
global or local estimates, and, if local, state the be checked by duplication of selected RC holes with
relevant tonnages, which should be relevant to additional equipment to settle and collect the
technical and economic evaluation. Documentation material in the outside return air stream for assay.
should include assumptions made and the procedures In addition, RPM recommends drilling a set of around
used. thirty diamond holes in locations spread evenly
throughout the deposit to be used to more
representatively investigate and quantify the grade
* These statements of relative accuracy and confidence adjustment factor prior to improving the
of the estimate should be compared with production classification to the Measured category in the more
data, where available. well-informed areas or proceeding to economic
evaluation or further feasibility studies for
development of the Project.
* The Mineral Resource statement relates to global
estimates of tonnes and grade.
* No production data was available for comparison.
--------------------------------------------------------------- -----------------------------------------------------------------
Refer AIM announcement of 26 February 2016 and ASX announcement of 29 February 2016
This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact rns@lseg.com or visit www.rns.com.
END
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